Apparatus for depositing a multilayer coating on discrete sheets

ABSTRACT

A tool for depositing multilayer coatings onto a substrate. The tool includes a housing defining a vacuum chamber connected to a vacuum source, deposition stations each configured to deposit a layer of multilayer coating on the substrate, a curing station, and a contamination reduction device. At least one of the deposition stations is configured to deposit an inorganic layer, while at least one other deposition station is configured to deposit an organic layer. In one tool configuration, the substrate may travel back and forth through the tool as many times as needed to achieve the desired number of layers of multilayer coating. In another, the tool may include numerous housings adjacently spaced such that the substrate may make a single unidirectional pass. The contamination reduction device may be configured as one or more migration control chambers about at least one of the deposition stations, and further includes cooling devices, such as chillers, to reduce the presence of vaporous layer precursors. The tool is particularly well-suited to depositing multilayer coatings onto flexible substrates, as well as to encapsulating environmentally-sensitive devices placed on the flexible substrate.

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to an apparatus fordepositing multilayer coatings onto sheet substrates and devices mountedthereon, and more particularly to an encapsulation tool that performsmultilayer coating processing while simultaneously reducing thelikelihood of individual layer contamination.

[0002] Multilayer coatings have been included in the packaging forenvironmentally sensitive products and devices to protect them frompermeation of environmental gases or liquids, such as oxygen and watervapor in the atmosphere, or chemicals used in product or deviceprocessing, handling, storage, or use. In one form, these coatings maybe made from layers of an inorganic metal or metal oxide separated bylayers of an organic polymer. Such coatings have been described in, forexample, U.S. Pat. Nos. 6,268,695, 6,413,645 and 6,522,067, and allowedU.S. patent application Ser. No. 09/889,605, all incorporated herein byreference. One method commonly used to apply thin multilayer coatings tovarious web substrates is the “roll-to-roll” method, which involvesmounting the continuous web substrate on a reel. A series of rotatingdrums are used to convey the substrate past one or more depositionstations. As the web passes around the drums in the system, polymerlayers are deposited and cured at one or more polymer deposition andcuring stations, while inorganic layers are deposited at one or moreinorganic layer deposition stations. The deposition and curing stationsare not separate chambers coupled together, but rather are adjacentlyspaced relative to one another within a single vacuum chamber. With suchan open architecture, efforts must typically be made to minimizemigration of the organic vapor which could otherwise lead to layer orsubstrate contamination. In addition, since vapor deposition imparts asignificant heat load to the receiving substrate, one or more of thedrums can be configured to provide a needed heat sink to controlsubstrate temperature. While the roll-to-roll method is capable of highproduction rates, its practical use is limited to substrates that arecontinuous lengths (rolls). In addition, the flexure inherent in theroll-to-roll approach makes it difficult to deposit coatings onto rigidsubstrates or to substrates supporting inflexible devices mountedthereto.

[0003] When the substrate to be coated is in the form of discretesheets, rather than a continuous web, another method, called the“cluster tool” method, is commonly used to apply the multilayer coatingsto the sheet substrate. The cluster tool method, which is commonly usedin the manufacture of semiconductor devices, involves the use of two ormore independent vacuum chambers connected together via commoninterface, where each vacuum chamber contains one or more depositionsources. In the cluster tool approach, discrete sheet substrates aremoved from one vacuum chamber to another to accept the different layersthereon, with the process being repeated as many times as necessary toproduce the desired built-up coating. One of the strong motivators fordeveloping the cluster tool approach was the need to isolate potentialcontamination sources between adjacent yet disparate layers, wheretypically isolation valves are placed between adjacent chambers. Infact, the use of cluster tool-based machinery for the barrier coatingindustry was based in part on the perception that organic and inorganicdeposition could not take place within a common vacuum chamber ifcontamination was to be avoided. Another attribute of the cluster toolapproach is that the potential for precise temperature control of thesubstrate is greater within each discrete vacuum chamber than it is forthe open chambers of the roll-to-roll configuration. While the clustertool approach has the benefit of producing relatively contaminant-freefinished products, the constant exchange of the sheet substrate from oneisolated vacuum chamber to another while maintaining a vacuum addsconsiderable complexity to design and control systems.

[0004] Accordingly, there is a need for a tool that can apply multilayercoatings to a sheet substrate and devices or products mounted on a sheetsubstrate that combines the speed and efficiency of roll-to-roll deviceswith the ability to prevent cross contamination inherent in clustertool-based machines.

SUMMARY OF THE INVENTION

[0005] This need is met by the apparatus of the present invention, wherethe individual layers making up the multilayer coating can be depositedin-line in an open (common environment) architecture. By avoiding thenecessity of having numerous decoupled stations, encapsulationproduction rates and overall tool simplicity is maximized, while propercontrol of the material being deposited meliorates individual layercontamination by minimizing the tendency of the material in gaseous formto disperse to adjacent deposition stations. The present inventors havediscovered that various isolation devices can be added to the vacuumchamber to reduce or eliminate the chance of interlayer contaminationwithout having to isolate adjacent deposition stations.

[0006] According to an aspect of the invention, a tool for in-linedeposition of multilayer coatings on a discrete sheet substrate isdisclosed. In the present context, an in-line tool is to bedistinguished from a roll-to-roll tool in that first, an in-line tool isconfigured to handle discrete sheets while the roll-to-roll tool handlescontinuous webs, and second, the deposition stations along an in-linetool generally follow a linear, planar path (which may encompass eitherunidirectional/one pass movement or a shuttling/multi-pass movement) sothat during coating processing the tool does not subject the substrate(and any devices mounted thereto) to overly curvaceous paths that mightotherwise be harmful to either the coating or the device encapsulated bythe coating. In this context, the deposition path is considered to besubstantially linear. An in-line tool is distinguished from a clustertool in that in the in-line tool, the deposition of the various layersof the multilayer coating occur in a continuous, sequential path whilein a common environment, whereas in a cluster tool, the various layersare deposited in autonomous chambers isolated from both the ambientenvironment and neighboring chambers. The tool includes a proximal endconfigured to accept the substrate, a distal end opposite the proximalend, and at least one housing disposed substantially between theproximal and distal ends. The housing defines a substantially lineardeposition path to facilitate transport of the substrate through thetool, and is made up of at least one of each organic layer depositionstation, curing station and inorganic layer deposition station, as wellas at least one contamination reduction means to control the migrationof material making up the organic layer from the organic layer stationin which the material originated. The housing further defines a commonvacuum throughout which the organic, curing and inorganic stations areplaced positioned such that at least the inorganic layer depositionstation and the organic layer deposition station are, upon operation ofa vacuum source coupled to the common vacuum, in vacuum communicationwith one another. The inorganic layer deposition station is configuredto deposit at least one inorganic layer of the multilayer coating, whilethe organic layer deposition station is configured to deposit at leastone organic layer of the multilayer coating, and the curing station isconfigured to cure the organic layer deposited by the organic layerdeposition station. Both of the organic and inorganic layer depositionstations are configured such that they can deposit layers onto thesubstrate. In the present context, deposition of a layer “onto” thesubstrate encompasses both application in direct contact with theunderlying substrate as well as application onto one or more layerspreviously deposited on the substrate as part of a contiguous stack. Inthis way, either the organic layer or the inorganic layer may bedeposited first, yet both layers, even in a multilayer configuration,are considered to be deposited onto the substrate. The substantiallylinear deposition path of the present in-line configuration is such thatphysical isolation within separate, autonomous stations is not required.

[0007] Optionally, the tool may include additional components, includingone or more mask stations. These may be made up of an organic maskplacement device and an inorganic mask placement device, each configuredto place an appropriately shaped and sized mask onto the substrate priorto entering the organic and inorganic stations, respectively. One orboth of the proximal and distal ends may be configured as an accumulatorsuch that it can contain a batch of the substrates at least before,after or between multilayer coating deposition steps. In the presentcontext, a “batch” of substrates encompasses one or more individualsubstrate sheets that are placed within the isolated, controlledenvironment of the tool such that they are processed in a single toolrun. Thus, whereas a plurality of substrates could include a continuousstream of such substrates being individually fed into the tool, a batchof such substrates is that subset of a plurality that is produced inquantities limited by the capacity of the accumulator rather than thesize of the continuous stream. In situations where both ends of the toolare accumulators, the tool can process a plurality (preferably two)substrate batches simultaneously. In the present context, the term“simultaneously” refers not to having individual substrates from each ofthe two batches be exposed to the same deposition concurrently (whichwould in essence amount to a degenerate case of the two batches), but tothe ability of the tool to sequence its various depositioning and curingsteps such that all of the substrates within one batch can be shuttledpast the appropriate station or stations and returned to one of theaccumulators prior to the next deposition step being performed on theother batch within the tool. Thus, between the time the substratebatches are loaded and isolated within the tool and the time they exitthe tool, more than one batch can be produced. The accumulators can befurther configured to reverse the substrate along the substantiallylinear deposition path such that multiple layers of multilayer coatingmay be deposited. As the first device along the in-line tool that thesubstrate encounters, the accumulator can be configured to at leastpartially isolate the one or more substrates from an ambient, externalenvironment. In the present context, partial environmental isolationincludes the ability of the accumulator to reduce at least one of thevacuum or temperature levels in the region that contains the substratedown to a level necessary to permit proper operating conditions for thesubstrate prior to or during the multilayer coating deposition process.The accumulator may include thermal control features to reduce thetemperature within the accumulator. With this feature, the accumulatoracts as a temperature control unit to counteract the increase intemperature experienced by the substrate or device due to the depositionprocess. The accumulator may further include an environmental isolationvalve such that once the substrate (or substrates) is placed within theaccumulator, the valve can be shut, after which temperature and vacuumlevels may optionally be changed.

[0008] The tool may further comprise at least one surface treatmentchamber configured to enhance the ability of individual layers of themultilayer coating to adhere to the substrate or an adjacent layer. Thesurface treatment chamber may be placed within the housing, theaccumulator or adjacent to either. The tool can be configured such thatthe inorganic layer is placed onto the substrate prior to the placementof the first organic layer. While the use of sputtering is beneficial inallowing the tool to function to apply multilayer barriers, other forms,including thermal evaporation, allow the tool to perform encapsulationfunctions as well without subjecting the environmentally sensitivedevice being encapsulated to harsh environments, e.g., high temperaturesand/or plasmas. Special measures may be undertaken to avoid damage tothe environmentally sensitive device (such as an organic light emittingdiode (OLED)) that can otherwise arise from being exposed to the plasmasand/or temperatures of the sputter coating process. In one approach, thefirst deposited inorganic layer can be deposited via thermal evaporationrather than sputtering. By way of example, since thermal evaporation isa currently-used approach for forming the metallic top electrode of anOLED, such an inorganic layer deposition approach could also be used asan encapsulation-enhancement approach. Unlike commonly-used oxides, suchas aluminum oxide (Al₂O₃), that are applied by reactive sputtering,inorganics such as lithium fluoride (LiF) and magnesium fluoride (MgF₂)(both of which are optically transparent) can also be applied viathermal evaporation to create a protective layer without having toexpose the environmentally sensitive device to the plasma. Similarly,the approach could utilize an inorganic transparent metal halide viathermal evaporation, a sputtered transparent inorganic or firstdeposited organic, or a simpler approach in which thermal evaporation isused for the first deposited inorganic. The latter would require a firstdeposited inorganic that can be applied by thermal evaporation andprovide a combination of adhesion and transparency.

[0009] In one form, the contamination reduction means is a thermalcontrol device disposed adjacent at least one side of the organic layerdeposition station, preferably disposed adjacent upstream and downstreamsides of the organic layer deposition station. By way of example, thethermal control means can be a chiller configured to reduce theatmospheric conditions within and around the organic layer depositionstation, or it could be a thermal mass. By way of example, a firstchiller can be located within the first migration control chamberlocated adjacent station inlet, with a second chiller located within thesecond migration control chamber adjacent station outlet. Other chillerplacement and configuration is also contemplated, depending on thesystem needs. For example, these chillers may be in the form of coldinert gas (such as nitrogen) injection devices placed upstream anddownstream of the organic deposition station. Besides thermal controldevices, the contamination reduction means can include at least onebaffle placed adjacent at least one side of the organic layer depositionstation such that a tortuous path is set up, thereby making it moredifficult for excess organic layer material to migrate out of theorganic layer deposition station and into other stations.

[0010] The tool can be configured to have the substrate shuttle back andforth through the housing as many times as required to deposit themultilayer coating on the substrate. To effect the shuttling movement,one or more conveyers extending through the one or more housings may beincluded to transport the substrate through at least a portion of thetool. The conveyor can be configured to move bidirectionally between theproximal and distal ends. The tool may also include a testing chamber tofacilitate testing of the resistance of the multilayer coating toenvironmental attack. Examples of environmental attack that multilayerbarrier coatings are configured to prevent include permeation by oxygenand water. Thus a current approach to testing permeation resistance isbased on vacuum deposition of a thin layer sensitive to oxygen or water(for example, calcium) followed by deposition of a multilayer barriercoating to produce a sample that can be tested. A test chamberfacilitating this approach contains a station for vacuum deposition ofthe thin sensitive layer onto uncoated substrates to produce test blanksthat have sensitivity similar to an OLED. The ability to prepare thetest sample in the same environment (vacuum that is maintained throughout the process) used for application of the multilayer barrier coatingincreases accuracy (validity) and reduces turnaround time for testresults.

[0011] A control system may be included to determine operability of thevarious tool components and process conditions within the housing, aswell as be responsive to process parameters, such as temperature,scanning speed, presence of contaminants, or the like. The vacuum sourcemay provide a different vacuum level during deposition of the inorganiclayer than during deposition of the organic layer. By way of example,the vacuum level during deposition of the inorganic layer can beapproximately 3 millitorr, while that during deposition of the organiclayer can be approximately 10 millitorr. In another option, theinorganic layer deposition station comprises a rotary sputtering source,which may include a rotatable cathode.

[0012] Preferably, the inorganic layer is deposited onto the substrateprior to the placement of the organic layer. The inventors havediscovered that placing an inorganic (such as an oxide) layer firstresults in improved adhesion between the substrate and between layers,as well as improved barrier properties. The inventors have furtherdiscovered that in situations involving encapsulation of an object (suchas an OLED) placed on the substrate, superior adhesion and barrierproperties are achieved using “inorganic first” approaches. Thus, whilethe inclusion of an organic layer continues to make valuablecontributions to the overall performance of the multilayer coating, theinventors' research suggests that attainment of a suitable base (orfoundation) for effectively isolating the barrier from undesirablecontributions from the underlying substrate (or device) may be bestachieved with one or more inorganic layer/organic layer pairs led by aninorganic layer. By placing an inorganic layer onto a substrate (such asglass or a plastic) first, the inventors have achieved adhesion tosubstrates, to devices placed on substrates, and between layers ofmultilayer environmental barriers, all of which withstand the physicaland thermal rigors of the environment in which they have to perform.Furthermore, when these layers form the surface upon which a device isplaced, they survive all of the processing associated with fabricationof the device. The inventors believe that at least one explanation maybe that migration of organic species from the substrate to thisfirst-applied layer is reduced compared to if the first layer is theorganic layer, and that such migration reduction is promotes andmaintains enhanced adhesion between the substrate and the first-appliedlayer. In addition, in cases involving deposition onto a device mountedon the substrate, the inventors believe that with a first depositedorganic layer, the layer does not adequately wet, or uniformly coat, thedevice surface. This could be due to species originating in the organiclayers of the device being coated, not having a suitable formulation forthe first deposited organic layer relative to the device, or acombination of both. On the other hand, an “organic first” approach (atleast in encapsulation situations) would reduce or even eliminate thepotential for damage to the device from the plasma used in depositinginorganic layers.

[0013] According to yet another aspect of the invention, a tool forencapsulating objects between a multilayer coating and a flexiblesubstrate is disclosed. The tool includes at least one housingsubstantially defining a common vacuum and a substantially lineardeposition path therein, a vacuum pump coupled to the vacuum chamber, afirst accumulator positioned upstream of the housing, and a secondaccumulator positioned downstream of the housing. The first accumulatoris configured to provide at least partial environmental isolation of thesubstrate from an external ambient environment once the substrate hasbeen placed in the substantially linear deposition path, while thesecond accumulator is configured to provide at least partialenvironmental isolation of the substrate from an external ambientenvironment, as well as to reverse the substrate along the substantiallylinear deposition path such that multiple layers of the multilayercoating may be deposited on the substrate. The housing is made up of atleast at least one organic layer deposition station, at least one curingstation, at least one inorganic layer deposition station, a mask stationconfigured to place an organic mask and an inorganic mask on thesubstrate and at least one contamination reduction device to control themigration of material making up the organic layer. Optionally, the toolmay further include a fixturing device positioned upstream of the firstaccumulator, while at least one of the accumulators may include athermal control device. Additionally, the first accumulator comprises asubstrate input path and a substrate output path, the substrate outputpath spaced apart from the substrate input path.

[0014] According to yet another aspect of the invention, anencapsulation tool for in-line depositing a multilayer coating on asubstrate to protect an object placed thereon is disclosed. The toolincludes one at least one housing substantially defining a common vacuumand a substantially linear deposition path therein, means for depositinga first material over the object while the object is in the at least onehousing, means for curing the first material while the object is in theat least one housing, means for depositing a second material over theobject while the object is in the at least one housing, means forproviding a vacuum in the at least one housing such that the means fordepositing first material, the means for depositing second material andthe means for curing the first material are in vacuum communication withone another, and means for controlling the migration of the firstmaterial from the means for depositing a first material. Optionally, theencapsulation tool is configured such that either the first or secondmaterial can be first applied to be adjacent the substrate, while thehousing can be configured as a plurality of housings sequentiallycoupled such that the common vacuum is common to each of the pluralityof housings. As with the previous aspects, at least one accumulator maybe included to at least partially isolate the substrate from an externalambient environment. The accumulator can be in selective vacuumcommunication with the housing, and may comprise a device configured toreduce the temperature within the accumulator.

[0015] According to still another aspect of the invention, a method ofdepositing a multilayer coating onto a substrate is disclosed. Theconfiguration of the tool is according to at least one of the previousaspects. The method includes the steps of loading a substrate into thehousing, providing at least a partial vacuum within the housing,introducing an inorganic material into the inorganic layer depositionstation, depositing at least a portion of the inorganic material as acomponent of the multilayer coating, introducing an organic materialinto the organic layer deposition station, depositing at least a portionof the organic material as a component of the multilayer coating, curingthe organic material that was deposited and controlling the migration ofexcess organic material out of the organic layer deposition station.Optionally, the method comprises the additional step of treating atleast one surface of the substrate prior to forming a first layer of themultilayer coating. In one form, the step of controlling the migrationof excess organic material comprises cooling at least a portion of thespace defined by the organic layer deposition station such that theportion of the excess organic material remaining in a vapor phase in andaround the organic layer deposition station is reduced. For example,chillers are placed in thermal communication with the space defined bythe organic layer deposition station. Baffles may be employed to lowerthe conductance of vaporous contaminants across adjacent stations byreducing the flowpath area between the stations through which the gasmay permeate. Additional steps may include placing an inorganic maskover the substrate prior to the step of depositing the inorganicmaterial, and placing an organic mask over the substrate prior to thestep of depositing the organic material. To reduce the incidence ofseepage and related capillary phenomena, masks may be stacked to make anundercut mask, or the organic mask may be removed prior to the curingstep. Removal of the mask prior to cure may also improve cure speed byeliminating mask shadowing of the edge of the organic material.Controlling the migration of excess organic material comprises coolingat least a portion of the space within the organic layer depositionstation, thereby effecting a reduction of excess organic materialremaining in a vapor phase in the organic layer deposition station.Chillers can be placed in thermal communication with the space definedby the organic layer deposition station to effect the cooling, whileadditional steps could be the placing a first accumulator upstream ofthe housing, placing a second accumulator positioned downstream of thehousing and incorporating a device into at least one of theaccumulators, the device configured to reduce the temperature on thesubstrate that arises from the steps of depositing the organic material,curing the organic material and the depositing the inorganic material.

[0016] According to still another aspect of the invention, a method ofencapsulating an object disposed on a substrate is disclosed. Theencapsulation tool can be configured according to thepreviously-described aspects. Steps of encapsulating an object includeloading the substrate with device mounted thereto into the housing,providing at least a partial vacuum within the housing, introducing aninorganic material into the inorganic layer deposition station,depositing at least a portion of the inorganic material, introducing aorganic material into the organic layer deposition station, depositingat least a portion of the decoupling organic material, isolating excessorganic material in the organic layer deposition station to reducecontamination in the organic layer deposition station due to the excess(i.e., not deposited) decoupling organic material and curing thedeposited organic material. Optionally, the steps of depositing theorganic and inorganic materials are repeated at least once, and thematerials corresponding to the two layers can be performed in anyalternating order. The organic material may be introduced into theorganic layer deposition station in vapor form, which can facilitate theevaporation of the organic layer through, bur not limited to, vacuumflash evaporation. The step of isolating at least a portion of theorganic material that was not deposited can be effected by chilling atleast a portion of the organic layer deposition station such that atleast a portion of the vapor form of the organic material that was notdeposited condenses. The organic material can be a polymer precursor,such as a monomer, while the inorganic material can be a ceramic. Thesematerial choices may furthermore applied to any of thepreviously-discussed aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a simplified view of a roll-to-roll tool according tothe prior art;

[0018]FIG. 2 is a simplified block diagram of a cluster tool accordingto the prior art;

[0019]FIG. 3 shows a cutaway view of an object encapsulated by amultilayer coating, where the deposition of the layers is by a toolaccording to an aspect of the present invention;

[0020]FIG. 4A is a diagrammatic view of an in-line encapsulation toolwith a single organic layer deposition station according to an aspect ofthe present invention;

[0021]FIG. 4B is a diagrammatic view of the positions of the substrateas it traverses back and forth through the tool of FIG. 4A during themultilayer deposition process, highlighting the tool's ability to handlemultiple batches of substrates simultaneously;

[0022]FIG. 4C shows a juxtaposition of the tool of FIG. 4A with asequencing diagram, showing the order in which various components in thetool are activated to produce a multilayer coating;

[0023]FIG. 5A is a diagrammatic view of the in-line encapsulation toolwith dual organic layer deposition stations according to an alternateembodiment of the present invention;

[0024]FIG. 5B is a diagrammatic view of the positions of the substrateas it traverses back and forth through the tool of FIG. 5A during themultilayer deposition process, highlighting the tool's ability to handlemultiple batches of substrates simultaneously; and

[0025]FIG. 6 is a perspective view showing the juxtaposition of theencapsulation tool with a controller of the present invention with anactive device deposition apparatus.

DETAILED DESCRIPTION

[0026] Referring first to FIG. 1, a roll-to-roll device 100 fordepositing multilayer coatings on a continuous web of substrateaccording to the prior art is shown. A web of substrate 110 passes overa distribution reel 120 and past a first organic layer depositionstation 125, curing station 130, inorganic layer deposition station 135,second organic layer deposition station 140 and curing station 145, andon to take-up reel 150. Optionally, the device 100 can include one ormore surface treatment devices (such as plasma source 155) to improvethe adhesion between the organic layer and the substrate 110. Theinterior of the device 100 defines a single chamber 160. A common vacuumis present among all of the aforementioned components. In one commonlyused process, the polymer multilayer (PML) process, an organic precursorused at the first and second organic layer deposition stations 125 and140 is flash evaporated such that when the organic precursor isintroduced into the vacuum chamber 160, it evaporates, where it can thenbe directed to the relatively cool substrate 110 for condensationthereon. The formation of a vapor phase (evaporation) is accomplishedthrough heating and increasing the surface area of the precursor, thelatter preferably by atomization into numerous tiny droplets thatincrease precursor surface area by several orders of magnitude.Concurrent with the marked increase in surface area is the introductionof the droplets into a vacuum environment. U.S. Pat. No. 4,722,515,hereby incorporated by reference, demonstrates the use of heat,atomization and an evacuated environment to effect evaporation oforganic precursor materials. Optionally, in the aforementionedevaporation, additional heating (thermal input) results from impingingthe output from an atomizer onto a hot surface. This by reference. Thecondensed liquid tends to planarize, thus removing a significantprocess, referred to as flash evaporation, is further taught by U.S.Pat. No. 4,954,371, also hereby incorporated portion of the inherentroughness of substrate 110. Curing and inorganic layer deposition stepstake place in the same environment.

[0027] Referring next to FIG. 2, a cluster tool system 200 of the priorart is shown. In a cluster tool configuration, a transport station 205is common to all of the deposition stations 210, 220 and 230 such thatthe materials unique to each station do not permeate the remainingdeposition stations. For example, discrete sheets of substrate (notshown) are sequentially routed between the transport station 205 and thefirst organic layer deposition station 210, inorganic layer depositionstation 220 and second organic layer deposition station 230 until thedesired finished product is obtained. Separate vacuums (not shown) areimposed on each of the deposition stations. This approach reduces thechance that the agents being deposited will be introduced at the wrongtime or location, thus promoting a relatively cross-contaminant-freefinal product, but does so at considerable increases in time andproduction cost.

[0028] Referring next to FIG. 3, the present invention can be used toencapsulate an environmentally sensitive device 90 between a sheetsubstrate 6 and multilayer permeation-resistant coating 9, or to rapidlydeposit the coating 9 directly onto the sheet substrate 6. By way ofexample, the environmentally sensitive device 90 can be an OLED. Thesheet substrate 6 can be configured to accept one or more of theenvironmentally sensitive devices 90 per sheet. Furthermore, the sheetsubstrate 6 can be either flexible or rigid; flexible substratesinclude, but are not limited to, polymers, metals, paper, fabric,flexible sheet glass, and combinations thereof, while rigid substratesinclude, but are not limited to ceramic, metals, glass, semiconductors,and combinations thereof. In the embodiment shown, the sheet substrate 6is made of glass, although encapsulated devices could also be placed ona plastic film support (such as polyethylene terepthalate, PET), where abarrier can be placed between the film and the device 90. The layersthat make up the multilayer coating 9 are organic layers 9A andinorganic layers 9B that can be stacked in any order, with each organiclayer 9A capable of being made of the same or different materials asother organic layers, while the same is true for the inorganic layers9B. The inorganic layer 9B is used to provide protection to theenvironmentally sensitive device 90, while the organic layer 9A bluntsor otherwise inhibits the formation of cracks or similar defects in theinorganic layer 9B. The organic layer 9A is typically in the range ofabout 1000-15,000 Å thick, while the inorganic layer 9B is typically inthe range of about 100-500 Å thick, although it may be thicker. Forexample, in situations involving device encapsulation (such as shown inthe figure), the first deposited inorganic layer 9B can be applied as arelatively thick layer (such as over a 1000 Å) to obtain a more thoroughencapsulation. It will be appreciated by those skilled in the art thatthe present drawing is shown in a simplified manner to highlight thevarious layers, and that the drawing is not necessarily in proportion toactual layer thickness or number. The number of organic and inorganiclayers 9A, 9B can be user-selected, governed by coverage and permeationresistance requirements.

[0029] The Organic Layer

[0030] In addition to performing the aforementioned crack-bluntingfunction, organic layer 9A may (as shown in the figure) be made thickerto provide, among other things, planarization. Moreover, the layer 9Acan provide thermal isolation of the underlying substrate or device,which is beneficial in reducing thermal inputs associated withsubsequent depositions of inorganic layers 9B. The benefit in coatingperformance from alternating discrete layers over fewer thicker layersmay be explained by simple redundancy, but could also be the result ofnucleation of a subsequently deposited inorganic layer 9B on organiclayer 9A initially deposited on first inorganic 9B layer with improvedbarrier properties that are not inherent in the bulk structure.

[0031] There are numerous plasma-based approaches to initiatingpolymerizations, cross-linking and cure of an organic layer 9A based onevaporation techniques. One approach is based on passing a flashevaporated organic material through a charged cathode/anode assembly toform a glow discharge plasma. In glow discharge plasma, a partiallyionized gas is used to bombard a substrate 6. Reactive species in thegas are chemically deposited onto a substrate 6 or a layer of coating 9thereon. After this, the organic material condenses to form an organiclayer 9A that self-cures by polymerization reactions initiated bycharged species resulting from plasma formation. The approach is taughtby U.S. Pat. Nos. 5,902,641 and 6,224,948, both hereby incorporated byreference. A variation of this approach is based on plasma generationwithin a working gas that is then directed at an organic layer depositedusing flash evaporation; this variation is taught by U.S. Pat. Nos.6,203,898 and 6,348,237, and U.S. Patent Application Publication2002/0102361 A1, all three hereby incorporated by reference. Organicprecursors suitable for forming organic layer 9A contain at least onespecies bearing an active functional group to enable reactions resultingin polymerization and/or cross-linking. Because it is desirable tocontrol the onset of these reactions, and the reactions will take placein a vacuum environment, addition reactions are generally preferred.Exemplary addition reactions include the polymerization of the acrylategroup (—O—CO—CR═CH₂, where R is typically H, CH₃ or CN), polymerizationof the vinyl group (R¹R²C═CH₂, where typically R¹ is H and R² is —O(oxygen linkage) or where R¹ is an aromatic or substituted aromatic andR is H or CH₃), ring opening polymerization of the cycloaliphatic epoxygroups and the reactions of isocyante (—NCO) functional species withhydroxyl (—OH) or amine (—NH₂) functional species. Ease of reaction andavailability favor acrylate and vinyl functional materials, but othermaterials may also be used.

[0032] The reactive species incorporated into suitable organicprecursors can be monomers (simple structure/single unit) bearing atleast one functional group, oligomers (composed of two to severalrepeating units) bearing at least one functional group, or polymersbearing at least one functional group. As used herein, monomer is meantto include species referred to as monomeric, and the terms oligomersand/or polymers are meant to include species referred to as oligomeric,polymeric, prepolymers, novalacs, adducts, and resins, when the lastmentioned bears functional groups. The reactive species (i.e., monomer,oligomer or polymer) can bear two or more similar or dissimilarfunctional groups, while suitable organic precursors can include two ormore of these reactive species. By way of example, these could be madeup of two or more monomeric species, one or more monomeric speciescombined with an oligomeric species or one or more monomeric speciescombined with a polymeric species. It will be appreciated by thoseskilled in the art that the numbers and natures of the reactive speciesthat can be used in combination are not subject to set limitations. Inaddition, the organic precursors may include one or more species thatare not polymerizable and/or cross-linkable and are liquids or solids.Examples include the aforementioned photoinitiators, which are speciesthat fragment to produce free radicals that induce free radical-basedreactions (including polymerizations) in response to UV exposure. Whensolid, these species may be present as dispersions, colloidaldispersions, or in solution, and may be ionic in nature, such as saltsof inorganic or organic species. When liquid, the non-reactive speciesmay be present as emulsions, as colloids, or as miscible components.

[0033] The liquid multilayer (LML) process, disclosed by U.S. Pat. Nos.5,260,095, 5,395,644 and 5,547,508 (incorporated herein by reference),bears some resemblance to the PML process previously described byemploying many of the same organic materials used in the PML's flashevaporation-based approach, but can further work with a range of highermolecular weight materials that can not be used via flash evaporation.In essence, the LML process involves applying a liquid material to asurface and then inducing a cure (polymerization) in contrast to the PMLapproach of condensing a flash evaporated organic and then inducing acure (polymerization).

[0034] The Inorganic Layer

[0035] The inorganic layer 9B depicted in the figure can be a ceramiclayer that can be vacuum deposited onto the top surface of device 90,onto the surface of sheet substrate 6, or onto the organic layer 9Aalready on sheet substrate 6. Vacuum deposition methods for theinorganic layer 9B include, but are not limited to, sputtering, chemicalvapor deposition, plasma enhanced chemical vapor deposition,evaporation, sublimation, electron cyclotron resonance-plasma enhancedvapor deposition, and combinations thereof. Sputtering typicallyinvolves the bombardment of a cathode material by gas ions in a lowpressure environment, thereby ejecting atoms of the cathode materialfrom the cathode surface. The ejected atoms then impinge upon asubstrate placed in their path, thereby resulting in a deposit of thecathode material atoms onto the substrate surface. Sputtering deviceshave used both electric and magnetic fields to accelerate the gas ionstoward the cathode surface. By passing a magnetic field through thecathode material, enhanced deposition rates can be achieved. Moreover,to avoid burn-through of the cathode material created by the fixedpresence of the adjacent magnets, the magnets were moved (such as beingrotated) relative to the target cathode. Specific refinements of thisidea include cylindrical tube cathodes that rotate about fixed magnets,thus promoting relatively even consumption of the cathode material. Byadding reactive capability, sputtering devices (including rotatablecylindrical devices) can be used to deposit ceramic and relatednon-metal materials, while the control of the buildup of electricallynonconductive layers of sputtered material avoids a drift in processparameters that would otherwise occur during deposition. Rotarysputtering is taught by U.S. Pat. No. 6,488,824 B1, the entiredisclosure of which is incorporated herein by reference.

[0036] Sputtering can be reactive (in the case of depositing of ceramicor dielectric materials, such as the oxides and nitrides of metals) ornon-reactive (where metals are deposited). In reactive sputtering, metalions are generated from a sputter source (cathode) and subsequentlyconverted in a reactive atmosphere to a metal compound deposited on thesubstrate. Use of oxygen as the reactive gas will result in thedeposition of a layer of metal oxide, while the use of nitrogen or acarbon source such as methane as reactive gases will result in thedeposition of layers of metal nitride or metal carbide respectively, andreactive gas mixtures can be use to produce more complex layers.Alternatively, a ceramic target can be RF sputtered onto the substrate6. In either case, the inert working gas is usually argon. In one form,the sputtered ceramic layer 9B can be Al₂O₃ because of its readyavailability and known deposition parameters. It will be appreciated,however, that other suitable deposition processes (such as theaforementioned thermal evaporation) and other inorganic layer materials(such as the aforementioned non-oxides MgF₂ and LiF) could also be used.As with the organic layer 9A, in situations involving deviceencapsulation, this first deposited layer 9B can be applied relativelythickly (such as over a 1000 Å) to obtain a higher qualityencapsulation, while subsequently deposited barrier stacks can providethe required environmental protection for the encapsulated device. Whileeither reactive or non-reactive sputtering can be used to facilitatedeposition of inorganic layer 9B on either sheet substrate 6 orenvironmentally sensitive device 90, the reactive approach is preferred,as this technique provides higher deposition rate and denser film for abetter barrier. Non-reactive processes can be advantageous whereconcerns about damage to the object being encapsulated are important.For example, if the environmentally sensitive device 90 is theaforementioned OLED, it might be necessary to protect it its uppercathode layer from the effects of a reactive gas. The closeness of thedeposition source to the surface being deposited on is determined inpart by which of the aforementioned deposition approaches are used. Byway of example, the inventors have discovered that an approximately sixinch sputter spacing between the two produces good results. Generally,the closer the surface is to the source, the higher the deposition rate,the trade-off being that if the surface and source are too close, highheat build-up can occur on the surface. In addition to closeness, theorientation of the surface relative to the source (whether above orbelow, for example) is dependent on the type of device beingencapsulated. Upward deposition has been used more extensively in thepast, because thermal evaporation is typically an upwardly-directedphenomenon. If the substrate is large, downward or sideways depositionmay instead be preferred. The energy input for the various depositionprocesses can also come in many forms, and can interact with otherdeposition considerations, such as whether reactive or non-reactivemethods are used. For example, a direct current (DC) input with areverse bias pulse is currently compatible with an Al₂O₃ layer, and isrelatively simple and provides a high deposition rate. This is alsobeneficial in arc suppression and control, as well as related particlegeneration. There are other possible energy sources for depositingceramic and related dielectric materials, such as alternating current(AC) or radio frequency (RF), especially for situations where arcing isto be avoided, and where the relatively high speed deposition rates ofpure metals is not required.

[0037] Referring next to FIG. 4A, an in-line encapsulation tool 2 fordepositing multilayer coatings on the sheet substrate 6 according to anaspect of the present invention is shown. The encapsulation tool 2, withproximal end 2A and distal end 2B, includes a deposition housing 3, theinside of which can be evacuated. Deposition housing 3 collectivelydefines an organic layer deposition station 10, curing station 20,inorganic layer deposition station 30 and mask station 60 such that allfour stations operate under a single vacuum. To ensure a common vacuumbetween the stations 10, 20, 30 and 60 inside deposition housing 3,openings between adjacent stations are coupled together to establish anopen flowpath between them. As used herein, “coupled” refers tocomponents that are connected to one another, but not necessarilydirectly connected. In the present context, intervening pieces ofequipment between the two pieces “coupled” together would not bedestructive of a coupled arrangement so long as some connectivity ispresent.

[0038] The configuration of the encapsulation tool 2 shown involves ashuttling of the sheet substrate 6 back and forth through the organiclayer deposition station 10, curing station 20, inorganic layerdeposition station 30 and mask station 60 over multiple bi-directionaltrips to achieve the desired number of deposited layers. As will bediscussed in more detail below, the encapsulation tool 2 can also beconfigured as a unidirectional device such that the requisite number oflayers can be deposited in a single pass through the system. Theinorganic layer deposition station 30 comprises a deposition chamber 32for depositing inorganic layer 9B, the details of which are discussedabove. The organic layer deposition station 10 includes a firstmigration control chamber 12, a deposition chamber 11 for depositingorganic layer 9A, and a second migration control chamber 14. Temperaturecontrol of the substrate is one way in which migration control of thematerial making up the organic layer 9A can be achieved. Since theorganic layer deposition step is very sensitive to substrate temperature(particularly elevated substrate temperatures), where cooler substrateswill condense more organic precursor uniformly and rapidly, particularemphasis has been placed on cooling the substrate. To that end, cooling(for example, in the form of chillers or thermal masses placed inmigration control chambers 12, 14 can be introduced along the depositionpath to keep the substrate 6 and the coating 9 or environmentallysensitive device 90 thereon from overheating. This cooling minimizes thedispersion of any organic precursor vapor to adjacent stations to avoidencapsulation tool hardware fouling. In addition, by reducing thequantity of excess organic precursor vapor before the sheet substrate 6moves to the next station, the encapsulation tool 2 effects aconcomitant reduction in the likelihood that subsequent coating layerswill become contaminated. Coolant (cryogenic or other) feed tubes (notshown) connect the chiller (not shown) to the first migration controlchamber 12 so that the feed tubes can disperse a chilling fluid (such asliquid nitrogen) over the top and bottom of the sheet substrate 6. Thefeed tubes have a supply and a return. The coolant is isolated from thevacuum.

[0039] In addition, cycle purge can be employed to reduce contaminationin the feed interface section. Baffles 15 situated on the proximal anddistal sides of organic layer deposition station 10 further contain thevaporous organic precursor within the localized space in which it isdeposited. The baffles 15 could also be added to other stations topartially shield the open flowpath defined by the contiguous entrancesand exits of the various stations from stray vapor dispersion. Theflowpath is open enough to ensure that common vacuum between thestations is not compromised. Once the deposition process is complete,the sheet substrate 6 goes into a second migration control chamber 14similar to that described in conjunction with the first migrationcontrol chamber 12 above.

[0040] Curing station 20 is configured to cure organic layer 9A that wasdeposited in organic layer deposition station 10. Upon curing of theorganic layer 9A, additional layers may be deposited. Cure orcross-linking results from free radical polymerizations that can beinitiated by exposure to an electron beam (EB) source or by exposure toan ultraviolet (UV) source when the aforementioned photoinitiators areincorporated into the organic precursor. In certain depositionscenarios, such as where a device 90 is placed on the substrate 6, theuse of UV is preferred to that of EB, as relying on UV exposure to curethe condensed layer rather than an EB source helps to avoid concernsover the impact of the more harsh EB exposure. By way of example, EBexposure can be up to several kilo-electron volts (keV) on theunderlying device 90. It will be appreciated by those skilled in the artthat polymerization (cross-linking) based on UV exposure is not limitedto free radical mechanisms. There are photoinitiators that liberatecationic initiators (so-called Lewis-acids, Bronstead-acids, oniumsalts, etc.) enabling the use of cationic polymerization mechanisms. Useof these curing mechanisms in combination with flash evaporation istaught by U.S. Patent Application Publication 2002/0156142 A1, herebyincorporated by reference. Cationic polymerization facilitates use of alarge family of vinyl functional and cycloaliphatic epoxy functionorganic materials that are not ideally used in free radicalpolymerizations, but are still considered addition polymerizations.

[0041] Mask station 60 can include inorganic mask placement device 65and organic mask placement device 67, each to overlay theenvironmentally sensitive objects 90 deposited on sheet substrate 6 withthin, card-like masks. The masks prevent deposition of organic layer 9Aonto selected regions of substrate 90, such as electrical contacts, andcan be used to define (control) the overlap relationship betweeninorganic layers 9B and organic layers 9A, where such relationship isbeneficial in edge seal design. In the case of the organic maskplacement device 67, the overlaid masks can further be used to allowselective exposure and subsequent cure of portions of the depositedorganic layer 9A. In the deposition of inorganic layer 9B, portions ofthe mask may effect protection of the environmentally sensitive objects90 (such as an OLED cathode) from heat or particulate matter by actingas shields, as they are placed between the source cathode and thesubstrate to be coated and act as a mask to limit (define) the area ofthe substrate exposed to the source.

[0042] The proximal end 2A of the encapsulation tool 2 can be configuredas an accumulator 40 to allow an interface of the deposition stations ofhousing 3 to upstream or downstream equipment, or to the ambientexternal environment, such as for loading and unloading substrate 6. Theaccumulator 40 acts as a wait station for one or more of the substrates6 that are about to be processed, providing a stable, relativelyisolated environment where, for example, temperature and atmosphericagitation reduction can be effected, thereby improving the overallquality of the deposition process. The accumulator 40 includes an inlet40A and an outlet 40B spaced apart from inlet 40A. The accumulator mayinclude isolation chambers 4 defined by isolation valves 17 such thatonce the substrate 6 is loaded in the accumulator 40, at least partialisolation from the ambient environment may commence. As previouslymentioned, vacuum and thermal control can be produced in the accumulator40. The thermal reduction can be achieved by thermal mass heat sinksthat are placed in contact with or adjacent the substrate 6 at one ormore discrete locations, or by a chilled fluid (such as liquid nitrogen)system. These heat sinks can be used to reduce the temperature of thesubstrate 6 prior to the substrate 6 entering the various depositionstations, as well as cool the substrate during the deposition process.

[0043] In addition to supporting at least partial environmentalisolation for the substrate 6, the accumulator 40 may also include oneor more surface treatment chambers 19 to improve the adhesion of one ofthe organic layer 9A or inorganic layer 9B to substrate 6. The surfacetreatment chamber 19 may be a plasma energy (glow discharge) source andmay use an inert working gas, a reactive working gas or a combinationtherefore. The energy source to generate the plasma can come from RF, ACand DC, and may include a downstream plasma source, where the plasma isgenerated remotely and delivered to remove organic contaminants that mayhave coated various components therein. The treating, which causesincreased surface energies accompanied by increased hydrophilicbehavior, enhances adhesion between the substrate and the first formedlayer, thereby enabling formation of a better bond therebetween. Insituations involving a flexible substrate, such as the aforementionedPET film, additional improvements in film compliance and contaminantreduction is also enabled by surface treating. This is important, asthese contaminants (typically in the form of low-molecular-weightspecies) are migratory, thus capable of spreading to other layers. Inaddition, the inorganic layers can be treated to effect enhancedadhesion with subsequently deposited organic layers. For encapsulation,it is probably sufficient to treat only the surfaces of the inorganiclayers of the multilayer coating. This is based on the inventors' beliefthat the improvements to adhesion occur by treating the inorganic layersurfaces rather than the surfaces of the organic layers. A secondaccumulator 50 can define the distal end 2B of encapsulation tool 2.This accumulator, while capable of possessing all of the features ofaccumulator 40, is preferably simpler, providing optional temperaturecontrol and turnaround and wait-state containment of one or moresubstrates 6.

[0044] Once the proper environmental conditions have been establishedfor the substrate 6 in accumulator 40, the substrate 6 is transportedalong conveyor 7 to housing 3, where, depending on the depositionstrategy, the layers 9A, 9B of multilayer coating 9 will be deposited.For example, an eleven layer coating 9 could be formed from five organiclayers 9A interspersed among six inorganic layers 9B. Furthermore, itmay be preferable to deposit the inorganic layer 9B as the first layeron the substrate 6, onto which alternating layers of organic andinorganic layers 9A, 9B may subsequently be placed. Contrarily, it maybe preferable to reverse the order, having the organic layer 9A as thefirst layer on the substrate 6. Although shown in a one-sidedconfiguration, the inorganic layer deposition station 30 can beconfigured to provide two-sided treatment of the substrate.

[0045] Next, the sheet substrate 6 travels to the deposition chamber 11within organic layer deposition station 10, to receive an organic layer9A of multilayer coating 9. The organic layer 9A is preferably depositedvia an evaporative process such as PML, where the precursor material canbe in the form of a liquid solution, liquid with solid dispersion orliquid with liquid-immiscible mixture. Evaporation may be performed bysupplying a continuous liquid flow of the organic layer precursormaterial into the vacuum environment at a temperature below both thedecomposition temperature and the polymerization temperature of theprecursor, continuously atomizing the precursor into a continuous flowof droplets, and continuously vaporizing the droplets in a heatedchamber having a temperature at or above a boiling point of theprecursor, but below a pyrolysis temperature.

[0046] Once the sheet substrate 6 reaches the accumulator 50 at thedistal end 2B of encapsulation tool 2, it may subsequently be sent in areverse direction in order to pass through curing station 20 to hardenthe organic layer 9A that was just deposited in the organic layerdeposition station 10. Similarly, such a configuration establishes acompact system for the deposition of additional layers 9A, 9B ofmultilayer coating 9 as the sheet substrate 6 can simply be turnedaround to pass through the existing components defined by the organiclayer deposition station 10, curing station 20 and inorganic layerdeposition station 30 in reverse order. The sheet substrate 6 can travelthrough the encapsulation tool 2 as many times as desired to receive theappropriate number and type of layers 9A, 9B of multilayer coating 9.The encapsulation tool 2 may also include other deposition stations (notshown) to deposit additional coatings on the sheet substrate 6including, but not limited to, scratch resistant coatings,anti-reflective coatings, anti-fingerprint coatings, antistaticcoatings, conductive coatings, transparent conductive coatings, andother functional layers. Additional equipment can be connected toencapsulation tool 2, including a testing (or measurement) chamber 8(shown later) that can be used for quality-control purposes, such as toprovide indicia of the adequacy of the multilayer coverage. For example,a calcium-based referee sample can be created to support oxygen andwater permeability tests of the multilayer coating that is being appliedvia the apparatus of this invention. Such additional deposition stations(if present) could be included either upstream or downstream of theaccumulator 50.

[0047] Control system 70, made up of individual controllers 70A-70N, isused to dictate process parameters, including the order of deposition ofthe inorganic and organic layers, as well as thermal, motion andutilities control. For example, thermal control 70D can include hardwareand software that is coupled to the thermal control devices in theaccumulator 40 to chill the substrate 6, while thermal control 70F and70H can be used to operate the contaminant reduction devices of themigration control chamber 12. Motion control 70M includes hardware andsoftware that tracks the position of the substrate 6 while beingtransported by conveyor 7 along the encapsulation tool 2. Utilitiescontrol 70N includes hardware and software to provide electrical power,process gas, vacuum, compressed air and chilled water to the individualstations. Similarly, the factory control interfaces external systems formaterial management and process status. The human machine interface(HMI) is the control panel, computer, software, screen, keyboard, mouseand related equipment that allows an operator to run the system. Thecontrol system 70 can shuttle the sheet substrate 6 (and anyenvironmentally sensitive device 90 thereon to be encapsulated, ifpresent) in any order to accommodate particular encapsulation or barrierdeposition configurations.

[0048] Referring next to FIG. 4B in conjunction with FIG. 4A, sixteensimplified steps showing the preferred deposition order of a two-layercoating 9 traversing an encapsulation tool 2 comprising a single organiclayer deposition station 10 are shown, noting with particularity thatthe device shown is capable of processing two batches of substrates 6A,6B simultaneously. The configuration of the encapsulation tool 2 shownin FIG. 4A with accumulators 40, 50 disposed on opposite ends of housing3 allows the substrate 6 to be routed in a bi-directional path throughthe encapsulation tool 2 as many times as needed to build up themultilayer coating 9. By having a second accumulator 50 disposed at thedistal end 2B of encapsulation tool 2, multiple batches of substrate 6can be loaded and processed simultaneously. It will be appreciated bythose skilled in the art that while the number of batches that can beproduced simultaneously in the tool of FIGS. 4A and 5A is preferably twoin number, the present device is not so limited, as additionalaccumulators and related isolation containers (none of which are shown)can be coupled to the existing tool to improve batch throughput.

[0049] In step 1 of the operation, the first batch 6A of sheetsubstrates 6 is loaded into accumulator 40 at proximal end 2A. Afterstable environmental conditions are established in the accumulator 40(such as temperature reduction, establishment of a predetermined vacuumlevel or the enhancement of surface properties in surface treatmentchamber 19), the sheet substrates 6 are moved sequentially past theorganic layer deposition station 10 and curing station 20 by a conveyor7 to the mask station 60. A pallet (not shown) to carry the sheetsubstrate 6 may contain holes therethrough to facilitate deposition ofthe layers of multilayer coating to the bottom of the sheet substrate 6,if desired, such as for two-sided coating deposition. Furthermore, anopen palette may allow the substrate to better “see” a chill plate orrelated thermal management device, thereby increasing the contributionof the chill plate to substrate thermal management.

[0050] Upon arrival at the mask station 60, the substrate 6 firstreceives a mask from inorganic mask placement device 55, after which itmoves (as shown in step 2) to inorganic layer deposition station 30 toreceive inorganic layer 9B. The energy applied (which may come from, byexample, a 2 kilowatt pulsed DC source applying a reactive coating in anexothermic reaction) to the substrate 6 from the inorganic layerdeposition station 30 may raise the temperature of the substratesignificantly.

[0051] To counteract this increase in temperature (which could otherwiseadversely impact the ability of the substrate to accept organic layer 9Ain subsequent deposition steps), the substrate is temporarily placed inaccumulator 50, as shown in step 3, where the thermal control featuresof accumulator 50 can be activated to both effect temperature reduction,as well as position the substrates 6 of batch 6A for a return tripthrough housing 3. At this time, as shown in step 4, a second batch 6Bcan be introduced into the inlet 40A of accumulator 40 at the proximalend of encapsulation tool 2, while the substrates 6 from batch 6Atraverse the reverse direction, receiving an organic layer coating fromorganic layer deposition station 10 with subsequent curing (notpresently shown). In step 5, the individual substrates 6 of second batch6B receive the same layer deposition as the first batch 6A did in step2. In step 6, the first batch 6A repeats that of step 2, being routedafter deposition to separate wait space in accumulator 50 so as not tomix with second batch 6B. After this step, the first batch 6A has aninorganic-led first organic/inorganic layer pair 9A/9B of coating 9. Assuch, a first inorganic layer 9B is part of the foundation pair(composed of first inorganic layer 9B and first organic layer 9A) thatdecouples or isolates the barrier coating 9 from the underlyingsubstrate 6 or device 90. In step 7, both batches 6A and 6B arecontained in accumulator 50, while in step 8, the first batch 6Areceives a second organic layer 9A and cure. In step 9, each substrate 6of the second batch 6B receives its first deposition of organic layer 9Auntil both batches 6A and 6B are stored in the accumulator 40, as shownin step 10. After step 11, the first batch 6A has two organic/inorganiclayer pairs 9A/9B of coating 9 disposed on the substrates 6. Step 12,once completed, leaves second batch substrates 6B with a first inorganiclayer 9B and a first organic/inorganic layer pair 9A/9B of coating 9.Step 13 is a wait state similar to that of step 7. Step 14 depicts thesubstrates 6 from first batch 6A exiting the encapsulation tool 2through outlet 40B in accumulator 40. In step 15 (which repeats theprocess of step 4), second batch 6B receives an organic layer 9A andcuring, while a new batch 6C is loaded into the inlet 40A of accumulator40. Step 16 shows the second and third batches 6B, 6C in a wait state inaccumulator 40. It will be appreciated that modifications to the abovesteps are possible; for example, if greater or fewer numbers of layersare required, the number of passes through the encapsulation tool 2 canbe varied accordingly. It will be appreciated by those skilled in theart that while the order (i.e., inorganic-led) of the foundation pair iscurrently preferred based on the substrates currently in use, thepresent system can be configured to provide an organic-first depositionstrategy for other substrate compositions that would require such anapproach.

[0052] Referring next to FIG. 4C, the juxtaposition of the encapsulationtool of FIG. 4A and a flowchart showing the shuttling of a substrate 6is shown, producing a four-layer coating 9. In this case, the inorganic(oxide) mask can be applied once, followed by applying (overlaying) theorganic mask only for inorganic (oxide) depositions. This configurationallows easy creation of undercut masks from two flat masks.

[0053] Referring next to FIGC. 5A and 5B, the encapsulation tool 2 hasmultiple organic layer deposition stations 10 such that, like theconfiguration shown in FIG. 4A, it can operate under a common vacuum.While this variant of the system includes extra components, it has theadvantage of having the housing 3 be repeated (not shown) such that allof the required layers of multilayer coating 9 can be deposited a fewerpasses, thus improving throughput. As an alternative, if enough housings3 are juxtaposed, the substrate 6 can be made to travelunidirectionally, thus simplifying the accumulators 40, 50 which wouldno longer require turnaround features. The number and arrangement ofsuch a station arrangement will depend on the required configuration ofthe layers in the multilayer coating 9, and can be configuredaccordingly. The encapsulation tool 2 can furthermore be configured todeposit the organic and inorganic layers 9A, 9B in any order, as well asto put an object either directly on the sheet substrate 6 or on one ormore layers of the multilayer coating. For example, while the preferredembodiment is to have the sheet substrate 6 be placed into theencapsulation tool 2 with the object to be encapsulated already mounted,the tool can also be configured to have the substrate 6 enter theencapsulation tool 2 empty, to have the object placed onto it once it isin the tool 2. Also, as with the configuration of the tool 2 as shown inFIG. 4A, baffles 15 can be used to straddle the various stations,especially the organic layer deposition station 10, to reduce migrationof the material used to make up the organic layer 9A. The simplifiedsteps of FIG. 5B mimic those previously described in conjunction withFIG. 4B, modified to take into account the additional organic layerdeposition station 10.

[0054] Referring next to FIG. 6 in conjunction with FIG. 3, theencapsulation tool 2 of FIG. 4A is shown connected to control system 70and an external material handling apparatus 80, all for depositing anenvironmentally sensitive device 90, such as an OLED, on sheet substrate6. The external material handling apparatus 80 can be configured toallow either manual or automated interfacing with the encapsulation tool2. Optional measurement chamber 8 is shown adjacent an accumulator 40 atthe end of the tool 2. In situations where the tool can be used forin-line device (OLED) manufacturing, an interface that maintains asuitable vacuum and includes handoff means to transfer substrates withdevices in place to the tool 2 would be employed. Although not presentlyshown, an accumulator 40 positioned between the two is advantageous,providing a means to deal with speed matching, problem resolution (suchas stop-and-fix), maintenance, cool downs, or the like. In anotherapproach (not shown), the tool 2 is separate from the device (OLED)manufacturing line. The manufacturing line will need a delivery withmeans for emplacing substrates with devices into a transport containerthat can be sealed and afterwards maintain a suitable vacuum. In thiscircumstance, the tool 2 will require a feed with means for receivingthe transport container, opening, and hand-off loading onto the tooltransport system. The line delivery and the tool receiver have toinclude means to establish and maintain suitable vacuums. Also, contraryto that of FIGS. 4A and 5A, isolation chambers 4 need not be part ofaccumulator 40, but may be separate devices.

[0055] While certain representative embodiments and details have beenshown for purposes of illustrating the invention, it will be apparent tothose skilled in the art that various changes may be made withoutdeparting from the scope of the invention, which is defined in theappended claims.

What is claimed is:
 1. A tool for in-line depositing a multilayercoating on a substrate, said tool comprising: a proximal end configuredto accept said substrate; a distal end opposite said proximal end; andat least one housing disposed substantially between said proximal anddistal ends, said housing defining a common vacuum and a substantiallylinear deposition path therein, said common vacuum configured to becoupled to a vacuum source and said substantially linear deposition patharranged to facilitate transport of said substrate through said housing,said housing comprising: at least one organic layer deposition stationconfigured to deposit at least one organic layer of said multilayercoating onto said substrate; at least one curing station configured tocure an organic layer deposited by said organic layer depositionstation; at least one inorganic layer deposition station configured todeposit at least one inorganic layer of said multilayer coating ontosaid substrate; and at least one contamination reduction device tocontrol the migration of material making up said organic layer from saidorganic layer deposition station in which said material originated. 2.The tool of claim 1, further comprising a mask station disposed in saidhousing, said mask station configured to place at least one mask on saidsubstrate.
 3. The tool of claim 2, wherein said mask station comprisesan organic mask placement device and an inorganic mask placement device.4. The tool of claim 1, wherein at least one of said proximal end andsaid distal end defines an accumulator, said accumulator configured tocontain a batch of said substrates at least before, after or betweensteps of deposition of said multilayer coating thereon.
 5. The tool ofclaim 4, wherein both of said proximal end and said distal end define anaccumulator.
 6. The tool of claim 4, wherein said tool comprises aplurality of organic deposition stations and a plurality of organiccuring stations.
 7. The tool of claim 4, wherein said tool is configuredto process a plurality of substrate batches simultaneously.
 8. The toolof claim 7, wherein said accumulators are further configured to reversesaid substrate along said substantially linear deposition path such thatmultiple layers of said multilayer coating may be deposited.
 9. The toolof claim 4, wherein at least one of said accumulators further comprisesa device configured to reduce the temperature within said accumulator.10. The tool of claim 4, wherein said accumulator comprises anenvironmental isolation valve.
 11. The tool of claim 4, furthercomprising at least one surface treatment chamber configured to enhancethe ability of individual layers of said multilayer coating to adhere tosaid substrate or an adjacent layer.
 12. The tool of claim 11, whereinsaid surface treatment chamber is disposed in said accumulator.
 13. Thetool of claim 12, wherein said surface treatment chamber comprises aplasma energy source.
 14. The tool of claim 12, wherein said surfacetreatment chamber comprises a thermal evaporation device.
 15. The toolof claim 12, wherein said thermal evaporation device is configured todeposit a non-oxide material.
 16. The tool of claim 15, wherein saidnon-oxide material comprises at least one of lithium fluoride ormagnesium fluoride.
 17. The tool of claim 1, wherein said inorganiclayer deposition station is configured to place an inorganic layer ontosaid substrate prior to the placement of an organic layer from saidorganic layer deposition station.
 18. The tool of claim 1, wherein saidat least one contamination reduction device is a thermal control devicedisposed adjacent at least one side of said organic layer depositionstation along said substantially linear deposition path.
 19. The tool ofclaim 18, wherein said thermal control device is disposed adjacentupstream and downstream sides of said organic layer deposition stationalong said substantially linear deposition path.
 20. The tool of claim18, wherein said thermal control device is a chiller.
 21. The tool ofclaim 1, wherein said contamination reduction device is at least onebaffle disposed along said substantially linear deposition path adjacentat least one side of said organic layer deposition station.
 22. The toolof claim 1, further comprising a conveyer extending through saidhousing, said conveyor configured to transport said substrate through atleast a portion of said tool.
 23. The tool of claim 22, wherein saidconveyor is configured to move bidirectionally between said proximal anddistal ends.
 24. The tool of claim 1, further comprising a testingchamber operably coupled to said tool, said testing chamber configuredto test permeation resistance.
 25. The tool of claim 24, wherein saidtesting chamber is configured to simulate environmental attack of atleast one of oxygen or moisture.
 26. The tool of claim 1, furthercomprising a control system configured to determine process conditionswithin said housing.
 27. The tool of claim 1, wherein said vacuum sourceis configured to provide a different vacuum level during deposition ofsaid inorganic layer than during deposition of said organic layer. 28.The tool of claim 27, wherein said vacuum level during deposition ofsaid inorganic layer is approximately 3 millitorr.
 29. The tool of claim27, wherein said vacuum level during deposition of said organic layer isapproximately 10 millitorr.
 30. The tool of claim 1, wherein saidinorganic layer deposition station comprises a rotary sputtering source.31. The tool of claim 30, wherein said rotary sputtering sourcecomprises at least one rotatable cathode.
 32. A tool for encapsulatingobjects between a multilayer coating and a flexible substrate, said toolcomprising: at least one housing substantially defining a common vacuumand a substantially linear deposition path therein, said substantiallylinear deposition path arranged to facilitate transport of saidsubstrate through said housing, said housing comprising: at least oneorganic layer deposition station configured to deposit at least oneorganic layer of said multilayer coating onto said substrate; at leastone curing station configured to cure an organic layer deposited by saidorganic layer deposition station; at least one inorganic layerdeposition station configured to deposit at least one inorganic layer ofsaid multilayer coating onto said substrate; a mask station configuredto place an organic mask and an inorganic mask on said substrate; and atleast one contamination reduction device to control the migration ofmaterial making up said organic layer from said organic layer depositionstation in which said material originated; a vacuum pump coupled to saidvacuum chamber; a first accumulator positioned upstream of said housing,said first accumulator configured to provide at least partialenvironmental isolation of said substrate from an external ambientenvironment once said substrate has been placed in said substantiallylinear deposition path; and a second accumulator positioned downstreamof said housing, said second accumulator configured to provide at leastpartial environmental isolation of said substrate from an externalambient environment, and to reverse said substrate along saidsubstantially linear deposition path such that multiple layers of saidmultilayer coating may be deposited on said substrate.
 33. The tool ofclaim 32, further comprising a fixturing device positioned upstream ofsaid first accumulator to accept said substrate therefrom.
 34. The toolof claim 33, wherein at least one of said accumulators comprises athermal control device.
 35. The tool of claim 32, wherein said firstaccumulator comprises a substrate input path and a substrate outputpath, said substrate output path spaced apart from said substrate inputpath.
 36. An encapsulation tool for in-line depositing a multilayercoating on a substrate to protect an object placed thereon, saidencapsulation tool comprising: at least one housing substantiallydefining a common vacuum and a substantially linear deposition paththerein, said substantially linear deposition path arranged tofacilitate transport of said substrate through said housing; means fordepositing a first material over said object while said object is insaid at least one housing; means for curing said first material whilesaid object is in said at least one housing; means for depositing asecond material over said object while said object is in said at leastone housing; means for providing a vacuum in said at least one housingsuch that said means for depositing first material, said means fordepositing second material and said means for curing said first materialare in vacuum communication with one another; and means for controllingthe migration of said first material from said means for depositing afirst material.
 37. The encapsulation tool of claim 36, wherein saidencapsulation tool is configured such that either said first or secondmaterial can be first applied to be adjacent said substrate.
 38. Theencapsulation tool of claim 36, wherein said at least one housing is aplurality of housings sequentially coupled such that said common vacuumis common to each of said plurality of housings.
 39. The encapsulationtool of claim 38, further comprising at least one accumulator configuredto at least partially isolate said substrate from an external ambientenvironment.
 40. The encapsulation tool of claim 39, wherein saidaccumulator is in selective vacuum communication with said housing. 41.The encapsulation tool of claim 40, wherein said accumulator comprises adevice configured to reduce the temperature within said accumulator. 42.A method of depositing a multilayer coating onto a substrate, saidmethod comprising: configuring an encapsulation tool to comprise: aproximal end configured to accept said substrate; a distal end oppositesaid proximal end; and at least one housing disposed substantiallybetween said proximal and distal ends, said housing defining a commonvacuum and a substantially linear deposition path therein, said commonvacuum configured to be coupled to a vacuum source and saidsubstantially linear deposition path arranged to facilitate transport ofsaid substrate through said housing, said housing comprising: at leastone organic layer deposition station configured to deposit at least oneorganic layer of said multilayer coating onto said substrate; at leastone curing station configured to cure an organic layer deposited by saidorganic layer deposition station; at least one inorganic layerdeposition station configured to deposit at least one inorganic layer ofsaid multilayer coating onto said substrate; and at least onecontamination reduction device to control the migration of materialmaking up said organic layer from said organic layer deposition stationin which said material originated; loading said substrate into saidhousing; providing at least a partial vacuum within said housing;introducing an inorganic material into said inorganic layer depositionstation; depositing at least a portion of said inorganic material ontosaid substrate as a component of said multilayer coating; introducing anorganic material into said organic layer deposition station; depositingat least a portion of said organic material onto said substrate as acomponent of said multilayer coating; curing said deposited organicmaterial; and controlling the migration of an excess of said organicmaterial out of said organic layer deposition station with saidcontamination reduction device.
 43. The method of claim 42, furthercomprising treating at least one surface of said substrate prior toforming a first layer of said multilayer coating thereon to enhanceadhesion between said substrate and said first formed layer.
 44. Themethod of claim 42, further comprising the steps of: placing aninorganic mask over said substrate prior to said step of depositing saidinorganic material; and placing an organic mask over said substrateprior to said step of depositing said organic material.
 45. The methodof claim 44, further comprising the step of stacking a plurality ofmasks to make an undercut mask.
 46. The method of claim 44, comprisingthe additional step of removing said organic mask prior to said curingstep.
 47. The method of claim 42, wherein controlling the migration ofexcess organic material comprises cooling at least a portion of thespace within said organic layer deposition station, thereby effecting areduction of excess organic material remaining in a vapor phase in saidorganic layer deposition station.
 48. The method of claim 47, whereinchillers are placed in thermal communication with said space defined bysaid organic layer deposition station to effect said cooling.
 49. Themethod of claim 42, comprising the additional steps of: placing a firstaccumulator upstream of said housing; placing a second accumulatordownstream of said housing; and incorporating a device configured toreduce a temperature on said substrate.
 50. A method of encapsulating anobject disposed on a substrate, said method comprising: configuring anencapsulation tool to comprise: a proximal end configured to accept saidsubstrate; a distal end opposite said proximal end; and at least onehousing disposed substantially between said proximal and distal ends,said housing defining a common vacuum and a substantially lineardeposition path therein, said common vacuum configured to be coupled toa vacuum source and said substantially linear deposition path arrangedto facilitate transport of said substrate through said housing, saidhousing comprising: at least one organic layer deposition stationconfigured to deposit at least one organic layer of said multilayercoating onto said substrate; at least one curing station configured tocure an organic layer deposited by said organic layer depositionstation; at least one inorganic layer deposition station configured todeposit at least one inorganic layer of said multilayer coating ontosaid substrate; and at least one contamination reduction device tocontrol the migration of material making up said organic layer from saidorganic layer deposition station in which said material originated;loading said substrate with said object disposed thereon into saidhousing; providing at least a partial vacuum within said housing;introducing a inorganic material into said inorganic layer depositionstation; depositing at least a portion of said inorganic material ontosaid substrate while said substrate is in said inorganic layerdeposition station; introducing an organic material into said organiclayer deposition station; depositing at least a portion of said organicmaterial onto said substrate while said substrate is in said organiclayer deposition station; isolating excess said organic material toeffect a reduction in organic material contamination; and curing saiddeposited organic material.
 51. The method according to claim 50,wherein said steps of depositing said organic and inorganic materialsare repeated at least once.
 52. The method according to claim 51,wherein said steps of depositing said organic and inorganic materialscan be performed in an any order.
 53. The method according to claim 50,wherein said organic material is introduced into said organic layerdeposition station in vapor form.
 54. The method according to claim 53,wherein isolating excess organic material comprises chilling at least aportion of said organic layer deposition station such that at least aportion of said excess organic material in said vapor form condenses.55. The method according to claim 53, wherein said organic material isdeposited via flash evaporation.
 56. The method according to claim 50,wherein said organic material is a polymer precursor.
 57. The methodaccording to claim 50, wherein said inorganic material is a ceramic.